1. Field of the Invention
The present invention relates to the field of polymer-infused carbon nanotube (CNT) array composite material and method of fabricating the same.
2. Description of the Related Art
Polymer-infused CNT array composites, membranes, and gaskets have many useful applications such as thermal interface materials (heat transfer elements for electronics), chemical and biological sensors (chemically modified CNTs as channels or electrical devices), filtration devices (nano-fluidic channels), reversible adhesives (artificial gecko feet) and electrical interconnects (high electrical conductivity).
Various methods are known in the art to infuse CNTs with a polymer material. These known methods include: (1) solution mixing of polymer and CNTs; (2) spin-coating; (3) melt blending and; (4) in-situ polymerization in the presence of CNTs. These methods of fabrication of polymer-infused CNT arrays have a number of shortcomings such as disruption of the order and uniformity of the CNT arrays, clumping of the CNT arrays, incomplete infusion of the polymer into the CNT arrays, and cracking of the resulting structure.
U.S. Pat. No. 6,407,922 discloses a thermally conductive material employing CNTs. The thermally conductive material includes a matrix material and CNTs incorporated therein. The thermally conductive material includes a first surface adjacent a heat source and a second opposite surface adjacent a heat dissipator. The first surface has a smaller area than the second surface. The CNTs each extend generally between the first and second surfaces. However, the CNTs are not regularly arranged in the matrix material, and can have poor orientation relative to the first and second surfaces. Consequently, heat cannot be uniformly and efficiently transferred from the first surface to the second surface.
U.S. Pat. No. 6,924,335 discloses a method for making thermal interface material including a polymer matrix and a CNT array. This method involves immersing the CNT array in a liquid pre-polymer solution to infuse polymer into a CNT array to form a polymer matrix embedded with CNTs. However, this method also fails to maintain the generally uniform flat surface and vertical alignment of the CNT array.
Therefore, there remains a need for a method to fabricate polymer-infused CNT array composites that can overcome at least the shortcomings discussed above. However, in view of the prior art considered as a whole at the time the present invention was made, it was not apparent to those of ordinary skill in the pertinent art how the identified need could be fulfilled.